For ZIP and GZIP formats 7-Zip provides
compression ratio that is 2-10 % better than ratio provided by PKZip
and WinZip

Self-extracting capability for 7z format

Integration with Windows Shell

Powerful File Manager

Powerful command line version

Localizations for 63 languages

Why do I recommend this?

While WinZip and PKZip are kind of the old grand-daddy's of the
file compression business, I found they only supported a small
subset
of the compression formats I needed.
Specifically, since I use Linux at work I was always running across
problems unpacking TAR, GZIP and BZIP files.
More recently, my adventures with online forums exposed me to
7Z and RAR formats.
What finally sealed my interest in 7-zip was the need for
portable applications running from a USB stick.